TABLE 3.

Model parameters for all fixed effects in the pH model for L. monocytogenes counts.

Response variable	Fixed effects	Levels	Estimate	Standard error	P-value	Significance
L. monocytogenes count (log cfu/g)	pH	6.5	Ref1
		6.0	−0.28	0.25	0.270
		5.5	−0.83	0.26	0.003	**
	Nisin	N2	Ref
		Y3	−1.89	0.33	<0.001	***
	Day	1	Ref
		7	0.46	0.25	0.074
		14	0.45	0.25	0.075
	Strain	10403S	Ref
		5621	0.19	0.11	0.081
		5623	0.13	0.11	0.229
		5624	0.22	0.11	0.045	*
		5625	0.21	0.11	0.052
	Inoculum4 (log cfu/g)		−0.02	0.08	0.838
	Milk apc5 (log cfu/mL)		−0.02	0.11	0.859
	pH:Nisin Y	6.5:Nisin Y	Ref
		6.0:Nisin Y	−0.28	0.35	0.432
		5.5:Nisin Y	1.44	0.35	< 0.001	***
	Nisin Y:Day	Nisin Y:1	Ref
		Nisin Y:7	−1.12	0.35	0.003	**
		Nisiin Y:14	−0.63	0.35	0.082
	Nisin Y:Strain	Nisin Y:10403S	Ref
		Nisin Y:5621	0.23	0.15	0.128
		Nisin Y:5623	0.24	0.15	0.111
		Nisin Y:5624	0.03	0.15	0.834
		Nisin Y:5625	0.61	0.15	<0.001	***

¹Ref indicates reference; therefore, estimates, standard error, and P-values were not calculated. ²N denotes the absence of nisin. ³Y denotes the presence of nisin. ⁴Average number (log cfu/g) of L. monocytogenes inoculated onto each cheese. ⁵Bacterial aerobic plate counts (apc; log cfu/mL) in milk before cheese was made. *** P < 0.001; ** P < 0.01; * P < 0.05